It is probably too much but I would love more visual racial distinction for the secret tech units.
The Dvar and Kir'ko units tend to take advantage of their racial features (though from the imperial archives image the Dvar celestial star guide seems bulkier though my impression was that they are also supposed to be a bit shorter) but the other more human factions seem to literally use the same model.
To give some examples:
Amazons: A more slender body shape, hair poking out from their helmets, bare feet (not on something like a purifier I'd guess)
Syndicate: indentured purifiers could take a que from indentured and have a helmet more similar to theirs or chest piece. They also seem to prefer (teamcolored?) tabards.
Assembly: bare unarmored limbs seems to be a good distinguisher here.
Vanguard: Baseline